Henry dreyfus



Fatented get. 23, 1928.

gig? are HENRY DREYFUS, OF LONDON, ENGLAND.

F'ELAIVIENTS OR THREADS OF CELLULGSE DERIVATIVES AND METHOD OF MAKING SAME.

1N0 Drawing. Application filed September 16, 1928, Serial No. 136,000, and in Great Britain March 29, 1826.

This invention relates to the manufacture of filaments or threads from cellulose others or cellulose esters, particularly cellulose acetates, and to Woven, knitted or other fabrics derivable therefrom by any usual textile operation.

In the manufacture of cellulose acetate or other cellulose esters, it is customary, after the acetylation or esterilication is complete, to subject the resulting product to a secondary or ripening treatment for the purpose o't imparting to it the solubility characteristics requisite for the production or solutions suitable for the manufacture or filaments, for example, by the dry spinning or evaporative method, or by any other appropriate method.

The viscosity of the ripened cellulose acetateas measured for example by comparison of the rate of flow ot a 6% solution in pure acetone at a temperature of 60 F. with the rate of flow of pure glycerinc under like conditions, the rate of flow of the glycerine being taken as 100varies to a marked extent in accordance with the manner in which the cellulose esters are prepared. In order to make an accurate comparison of the relative viscosities of di'tlierent cellulose esters were the most viscous then known and which can only be produced by the processes described and clain'ied in these specifications, said cellulose acetates or other esters varying in viscosity from about to 100 or even more, but usually being about 20 to 30 in the case of acetates intended for the production 01 spin- 7 ning solutions "for use in making filaments of artificial silk.

In mv British latent No. 267,562 and my U. S. ll'iltent Application S. No. 533,016 of 18 April, 1.928, 3. class *ibed cellulose ac Which, both before and after ripening in the ordinary Way, are of enormously high viscosity, going up to 200, 300 and 400, and even higher.

These products are very valuable as they consist of cellulose acetates in Which the origi nal cellulose molecule is much more preserved than in the acetates previously known. -While however, these acetates after ripening in the usual manner are soluble in solvents such as acetone to term solutions of the requisite concentration for technical use, ranging, for example, from 10% to 20% or or or even greater concentration, the resulting solutions are of very high viscosity.

1 have now found that spinning solutions made from cellulose acetates of very high viscosity can be improved by the addition of small proportions of solvents or plastieisers, such for example as triacetine and diacetine, of hi gher boiling point than the volatile solvents usually employed in the manufacture of spinning solutions.

According to this invention therefore in making spinning solutions from cellulose ethers or cellulose esters, particularly cellulose acetates, oi a viscosity exceeding about 50, and especially cellulose acetates having a viscosity over about 100 for instance 150, 200 or 400, there is incorporated in the spinning solution a small proportion of a solvent or plasticiser of higher boiling point than the volatile solvent or solvents used in the spinning solution.

Particularly of interest are the results which have been obtained by the use of high boiling solvents which have a higher solvent power for cellulose esters than the volatile solvent employed in making the spinning solution, that is to say, high boiling solvents the addition of which to the spinning solution may also lower its viscosity. The higher the solvent power of the: added high boiling sol vent, the greater is its influence on the spinning qualities of the spinning solution.

Any high boiling solvents or plasticisers for cellulose others or esters that are soluble in the spinning solution may be used; for instance, in making spinning solutions containcellulose acetate of very high. viscosity, triacctine, diacetine, mono oil, :methyl (or ethyl) toluene or xylene) si.,xphonamide, or

other known high boiling solvents or plastifiers may be employed.

The quantity of high boiling solvent or plasticiser is of importance. It is found that as the quantity of high boiling solvent or plasticiser added is increased from more upwards, a particular stage is reached beyond which the strength of the filaments decreases gradually thereafter with successive increments in the quantity of high boiling solvent or plasticiser in the spinning solution.

As a general indication it may be stated that in the case of cellulose acetate the proportion of high boiling solvent or plasticiser usually employed does not exceed. about 5% though it may sometimes reach 10% or 15% and preferably is about to 5% by weight of the cellulose acetate.

The proportion of high boiling solvent or plasticiser added to the spinning solution,

however, depends upon the grade of cellulose acetateor other cellulose derivative used and upon the nature of the high boiling solvent or plasticiser. Broadly speaking, in the case of solvents or plasticisers which are not evaporated to a substantial extent by dry spinning under ordinary conditions, proportions ranging up to about 5% or occasionally 10%, and preferably of about to 3% or 5% by weight of the cellulose derivative are employed. In the case of solvents or plasticisers that volatilize to some extent during the spinning operation, larger proportions may be adopted.

In applying these general indications to any particular case, it must be borne in mind that the quantity of high boiling solvent or plasticiser employed depends on the quality of the cellulose acetate or other cellulose derivative and the nature of the high boiling solventor plasticiser, and particularly on its solvent power for the cellulose derivative. The amount actually employed should be carefully chosen so that the filaments obtained by spinning the resulting solutions do not show a substantial, decrease in strength. The spinning solutions so prepared may be extruded through jets into a gaseous atmosphere .in which the filaments are solidified by evaporation of the acetone or other volatile solvents employed, or may be spun into filaments in any other appropriate manner.

The resulting filaments may be treated for the complete or partial removal of high boiling solvent or plasticiser by washing or extraction with a liquid which is a non-solvent for the cellulose derivative but which is capable of removing or dissolving the high boiling solvent or plastifier. When water soluble solvents or plastifiers such as triacetine, diacetine etc. are used, a simple washing-operation is sufiicient for their removal. Methyl (or ethyl) toluene or xylene) sulphonamide similarly can be removed by scouring with dilute alkali. The washing out or extraction of the high boiling solvent or plasticiser is preferably effected when the artificial silk is in the form of yarns, but may be performed after the silk has been manufactured into Woven or other fabrics.

As high boiling solvents or plasticisers, diacetine, triacetine and the aforementioned sulphonamides have proved to be of considerable value since they are sufiiciently soluble in water or dilute alkali to enable them to be removed by-anordinary washing operation.

The high boiling solvents or plastifiers, especially if present in very small proportions only, maybe allowed to remain in the filaments, but an increase in the strength of the filaments is found after the filaments tificial filaments previously produced, as

might be expected from the very high viscosity of the cellulose derivatives used.

The manner in which the invention can be carried into effect can be illustrated by the following examplesflt being understood that these are given only by way of illustration and can be varied Widely.

Ewample 1.

parts by weight of cellulose are treated with 900 to 1000 parts by weight of glacial acetic acid, 200 to 250 parts by weight of acetic anhydride, and 3 to 10 parts by weight of sulphuric acid at an initial temperature of 0-5 C. which may beallowed to rise to 10 to 15 (1. or even higher towards the close of the acetylation. When the acetylation is complete, the excess of acetylating agent destroyed by the addition of water and the mixture is allowed to stand at about 20 0., until the required solubility characteristics are developed. The acetylation solution can also be treated by neutralizing the effect of the condensing agent partially or completely and afterwards conducting the secondary treatment either at ordinary temperature or with heating to accelerate the reaction as de scribed inmy U. S. Patent N 0. -1,21?,722.

100 grams of cellulose acetate prepared in the manner described above are dissolved in about 300 to 500 grams of acetone, and between about 1 to 5 grams of triacetine or mono-oil, or of the aforementioned sulphonamides are added to the resulting solution.

Emample 2.

100 grams of eelluloseacetate prepared as described in Example 1, are dissolved in about 700 to 900 grams of acetone, and between about 2 to 5 grams of diacetine are added to the solution.

The filaments or threads obtained in accordance with this invention, after the removal of the high boiling solvent or plasticiser for example by washing, are of greater strength than any previously obtainet threads having been produced with strengths 0:5 1%, 1.8, 2, and even 2.2 or more times the strength of any previously known threads made from cellulose acetate.

lVhile as above stated, this invention relates principally to tne incorporation of high boiling solvents or plasticisers in spinning solutions containing cellulose derivatives of every high viscosity, it is also possible to produce similar results, though in a smaller de- Ill ill

gree, by the addition to the spinning solutions of high boiling liquids that are non-solvents for the cellulose derivatives, but are soluble in the spinning solutions, such, for example, as oils.

While the invention has been described more particularly with reference to the high viscosity acetates obtained in accordance with my British Patent No. 207,562 and my U. S. Patent Application S. No. 633,016 of 18th April,'1923, it is to be understood that it is applicable generally to cellulose acetates and other cellulose esters and celluose ethers of very high viscosity ashereinbeiore described.

It isalso to be understood that the invention includes not only the filaments and threads produced from the new spinning solutions herein described, but also woven, knitted or other fabrics made from or containing such filaments or threads.

lVhat I claim and desire to secure by Letters Patent is 1. A process for the manufacture of artilicial filaments or threads from organic substitution derivatives of cellulose of viscositics exceeding about 50, which comprises spinning solutions of said cellulose derivatives comprising less than about 15% calculated on the weight of the cellulose derivatives of a high boiling liquid that is not completely removed during the spinning operation.

2. A process for the manufacture of artificial filaments or threads from cellulose esters of viscosities exceeding about 50, which comprises spinning solutions ozt said cellulose esters comprising less than about 15% calculated on the weight of the cellulose esters of a high boiling liquid that is not completely removed during the spinning operation.

3. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of viscosities exceeding about 50, which comprises dry spinning solutions of said cellulose derivatives in volatile solvents, said solutions comprising less than about 15% calculated on the Weight of the cellulose derivatives of a high boiling liquid that is not completely volatilized during the spinning operation.

4.. A process for the manufacture oi artificial filaments or threads from organic substitution derivatives of cellulose 0t viscosities exceeding about 50, which comprises dry spinning solutions of said cellulose derivatives in volatile solvents, said solutions comprising less than about 15% calculated on the weight of the cellulose derivatives of a high boiling plasticiser for said cellulose derivatives that is not completely volatilized during the spinning operation.

5. A process for themanutacture of artificial filaments or threads from cellulose es ters of viscosities exceeding about 50, which comprises dry spinning solutions of said cellulose esters in volatile solvents, said solutions comprising less than about 15% calculated on the weight of the cellulose esters of a high boiling plasticiser for said cellulose esters that is not completely volatilized during the spinning operation.

6. A process for the manufacture of artificial filaments or threads from cellulose acetatcs of viscosities exceeding about 100, which comprises dry spinning solutions of said cel lulose acetates in volatile solvents, said solutions comprising less than about 15% calculated on the weight of the cellulose acetates of a high boiling solvent for said cellulose acetates that is not completely volatilized during the spinning operation.

7. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose ot viscosities exceeding about 50, which comprises spinning solutions of said cellulose der1va tives con'iprising less than about 15% calculated on the weight of the cellulose derivatives of a high boiling liquid, and removing the high boiling liquid from the resulting filaments or threads after the completion of the spinning operation.

8. A process for the manufacture of artificial filaments or threads from cellulose esters of viscosities exceeding about 50, which comprises dry spinning solutions ol? said cellulose esters in volatile solvents, said solutions comprising less than about calculated on the weight of the cellulose esters of a high boiling p-lasticiser for said cellulose esters, and removing the plasticiser from the resulting filaments or threads alter the completion of the spinning operation.

9. A process for the manufacture of artificial filaments or threads from cellulose acetates of viscosities exceeding about 100. which comprises dry spinning solutions of said cellulose derivative acetates in volatile solvents, said solutions comprising less than about 15% calculated on the weight of the cellulose acetates of a high boiling pla ticiser for said cellulose acetates, and removing the Ill) plasticiser from the .resulting filaments or threads after the completion of the spinning operation.

- 10. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of viscositie-s exceeding about 50, which comprises dry spinning solutions of said cellulose derivatives in volatile solvents, said solutions comprising a small proportion of a high-boiling plasticiser for said cellulose derivatives, and removing the plasticiser from the result ing filaments or threads by washing.

1].. A process for the manufacture of artificial filaments or threads from cellulose acetates of viscosities exceeding about 100, which comprises dry spinning solutions of said cellulose acetates in volatile solvents,

said solutions con'iprising a small proportion of a high-boiling plasticiser for said cellulose acetates, and removing the plasticiser from the resulting filaments or threads by washing.

12. A process for the manufacture of artificial filaments or threads from organic sub st-itution derivatives of cellulose of viscosities exceeding about 50, which compris dry spinning solutions of said cellulose derivatives in volatile solvents, said solutions comprising from about to about 5%, calculated on the weight of the cellulose derivatives, of a high boiling liquid that is not completely volatilized during the spinning operation.

13. A process for the manufacture of artificial filaments or threads from cellulose acetates of viscosities exceeding about 50, which comprises dry spinning solutions of said cellulose acetates in volatile solvents, said solutions comprising from about to about 5%, calculated on the weight of the cellulose acetates, of a high boiling solvent for said cellulose acetates that is not completely volatilized during the spinning operation.

ll. A process for the manufacture of artificial filaments or threads from cellulose acetates of viscosities exceeding about 50, which comprises dry spinning solutions of said cellulose acetates in volatile solvents, said solutions comprising less than about 10% of a higlnboiling liquid, calculated on the weight of the cellulose acetates, and removing the l'iigh-boiling liquid from the resulting filaments or threads after the completion of the spinning operation. 15. A process for the manufacture of artisolvent from the resulting filaments or threads by washing.

16. A process for the manufacture of artificial filaments or threads from cellulose acetates of viscosities exceeding about 50, which comprises dry spinningsolutions of said cellulose acetates in volatile solvents, said solutions comprising from-about to about 5% of a high-boiling solvent for said cellulose acetates,calculated on the weight-of the cellulose acetates, and removing the high boiling solvent from the resulting filaments or threads after the completion of the spinnin operation.

17. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of viscosities exceeding about 50, which comprises producing filan'ients or threads containing a small proportion of high-boiling liquid, and

removing the high-boiling liquid from the filaments or threads after the completion of the spinning operation. 1

18. A process for the manufacture of artilicial filaments or threads from organic substitution derivatives of cellulose of viscosities exceeding about 50, which comprises producing filaments or threads containing a small proportion of high-boiling plasticiser for said cellulose derivatives, and removing the high-boiling plasticiser from the result- .ing filaments or threads after the completion of the spinning operation.

19. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of viscosities exceeding about 50, which comprises producing filaments or threads containing less than about 10% of high-boiling plasticiser for said cellulose derivatives, and removing the high-boiling plasticiser from the filaineuts or threads after the completion of the spinning operation.

20. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of viscosities exceeding about 50, which comprises pro ducing filaments or threads containing between about to 3% of high-boiling plasticiser for said cellulose derivatives, and afterwards removing the plasticiser from the filaments by washing.

21. A process for the manufacture of artificial filaments or threads from cellulose ace tates of viscosities exceeding about 50, which comprises producing filaments or threat s containing less than about 10% of high-boiling plasticiser for said cellulose acetates, and removing the high-boiling plasticiser from the filaments or threads after the completion of the spinning operation.

22. A process for the manufacture of artificial filaments or threads fron'i cellulose acetates of viscosities exceeding about 50, which comprisesdry spinning solutions of said cellUH Ii I) lulose acetates in volatile solvents, said solutions comprising less than about 10% of a polyacetyl derivative of glycerine, calculated on the weight of the cellulose acetates.

23. A process for the manufacture of artificial filaments or threads from cellulose acetates of viscosities exceeding about 50, which comprises dry spinning solutions of said cel lulose acetates in volatile solvents said solutions comprising between about and about 3% of apolyacetyl derivative of glycerine, calculated on the weight of the cellulose acetates.

2 1-. A process for the manufacture of artificial filaments or threads from cellulose acetates of a viscosity exceeding about 50, which comprises dry spinning solution of said cellulose acetates in volatile solvents, said solutions comprising between about 5% and about 5% of a polyacetyl derivative of glycerine calculated on the weight of the cellulose acetates, and removing the polyacetyl derivative of glycerine from the resulting filaments or threads by washing.

25. Artificial filaments or threads comprising an organic substitution derivative of cellulose of a viscosity exceeding about 50, and less than about of a. high-boiling plasticiser for said cellulose derivative.

26. Artificial filaments or threads comprising a cellulose. ester of a viscosity exceeding about 50. and between about to 5% of a high-boiling plast-iciser for said cellulose ester.

27. Artificial filaments or threads comprising a cellulose acetate of a viscosity exceeding about 100 and between about to about 3% of a polyacetyl derivative of glycerlne.

28. A process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of high viscosity which comprises spinning solutions-of said cellulose derivatives containing a sub stance that is a solvent for said cellulose derivatives and which is not volatile at the spinning temperature.

29. A process for the manufacture of artificial filaments or threads from cellulose acetate of high viscosity which comprises spinning solutions of said cellulose acetate containing a substance which is a solvent for said cellulose acetate and which is not volatile at the spinning temperature.

30. A. process for the manufacture of artificial filaments or threads from organic substitution derivatives of cellulose of viscosities exceeding about 50 which comprises spinning solutions of said cellulose derivatives containing a substance that is a solvent for said cellulose derivatives and which is not volatile at the spinning temperature.

31. A process for the manufacture of artificial filaments or threads from cellulose acetate of viscosities exceeding about 50, which comprises spinning solutions of said cellulose acetate containing a substance that is a solvent for said cellulose acetate and which is not volatile at this spinning temperature.

In testimony whereof I have hereunto subscribed my name.

HENRY DREYFUS. 

